| abstract |
A thermosetting acrylic powder coating composition contains an acrylic copolymer of a monoethylenically unsaturated monomer having at least one epoxy group and at least one monoethylenically unsaturated monomer which is free of epoxy groups, a carboxy-terminated primary crosslinking agent, a supplementary crosslinking agent having at least one functional group which can react with either hydroxyl groups or carboxylic acid groups, and at least one ultraviolet light stabilizer or ultraviolet light screener capable of preventing degradation of the coating by ultraviolet light. An acrylic copolymer of methyl methacrylate, n-butyl methacrylate, and glycidyl methacrylate is favored. Preferably, the composition contains a combination of ultraviolet light stabilizer and ultraviolet light screener, is nonpigmented, and provides a clear, glossy, and durable film useful as the clear coat of a clear coat/color coat automobile finish. |